DJI Mini 3 pro landing problem

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Marvelmind Robotics

Hello

I' m developing an Android app based on MSDK v5.9.0 example to control DJI Mini 3 pro via RC-N1 controller.

The app executes takeoff, enables virtual stick mode, control drone movement using virtual stick commands, and finally executes landing.

The problem is on the landing stage - the function basicAircraftControlVM.startLanding returns success, but the drone in most cases doesn't execute landing - sometimes it only slightly changes its altitude, sometimes keeps hovering in the same point.

If I'm check FlightControllerKey.KeyIsLandingConfirmationNeeded, in most cases it returns that landing confirmation is not required, I thought it should mean the landing conditions are good.

In any case, calling FlightControllerKey.KeyConfirmLanding doesn't solve the problem - drone continues to hover and doesn't land.

FlightControllerKey.KeyFlightMode all time stays in LANDING_AUTO mode, I never seen it in LANDING_FORCED state.

Please help, what else I can check and execute to execute forced landing when I'm sure the landing conditions are ok?

 

 

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10 comments

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  • DJI Developer Support
    Once the aircraft has entered this state, are you able to use the remote control to make the aircraft land? You can check if this article might be helpful to you：https://sdk-forum.dji.net/hc/en-us/articles/14253788960025-How-to-achieve-forced-aircraft-landing
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  • Marvelmind Robotics

    Thank you for the answer. The article is helpful, KeyLandingProtectionState allows us at least to know the status of the landing execution. We didn't try remote controller to land, because we want to execute all the flight programmatically - from takeoff to landing.

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  • DJI Developer Support
    You can try using the remote control to attempt to make the aircraft land. This way, you can at least determine if the aircraft can execute a landing through forced descent.
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  • Marvelmind Robotics
    • Edited

    Thank you for the suggestion. We tried to land using remote control - same problem as with landing from the application. I most cases drone is very close to land, but doesn't finish it and hovers on the height 2-3 cm from the surface. Also in flights  under control from the application we checked FlightAssistantKey.KeyLandingProtectionState from the article you referenced - it stays in SAFE_TO_LAND  state when the drone keeps hovering on the 2-3 cm height and doesn't finish landing - very strange. FlightControllerKey.KeyFlightMode stays in AUTO_LANDING state at that time. Have you any more suggestions how to force the landing in such cases? Thank you in advance.

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  • DJI Developer Support
    At what altitude above the ground do you call the landing interface? And do you call the landing interface after exiting the virtual joystick mode?
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  • Marvelmind Robotics

    Thank you for the answer. We tried to disable virtual stick before landing, but this doesn't help - same issue, drone starts to descend, but doesn't finish and keeps hovering on altitude of 2...3 cm. When we firstly call landing, the drone is on altitude from 1.5 to 2 meters. When drone fails to land and hovering on altitude 2...3 cm, we repeat the landing command multiple times, but in most cases it doesn't help. Sometimes it finishes landing after 5..10 repeats of the landing command. Do you have any more suggestions? Thank you.

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  • DJI Developer Support
    Would you be willing to record a short video for us to directly understand the aircraft's performance? If you are unable to land the aircraft using the SDK, could you switch to DJI Fly to check its prompts? Here is the upload link:https://pan-sec.djicorp.com/s/x6TA4jzwMCTdXRH password:dji123
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  • Marvelmind Robotics

    Thank you. I uploaded the video with failed landing to the address you specified.

    Unfortunately our drone damaged one of its arms after a crash, so we can't do further test with DJI Fly until repair or getting a new drone.

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  • DJI Developer Support
    I will provide the video to the technical support team for the drone for verification. Please wait for a while.
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  • DJI Developer Support
    The technical support team for the drone thinks that the aircraft did not enter landing mode after reviewing the video. We may need the flight logs to investigate this issue further. Since the SDK team is unable to parse the flight logs for the DJI MINI 3 PRO, I recommend that you reach out to support@dji.com. The support email is for after-sales technical support for drones.
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